The present invention relates generally to cross-connect systems and, more specifically, to systems and methods for selectively restricting patch access to communication lines and for providing redundant supply power to communication line access devices.
The term DS-1 refers to a telecommunications protocol standard for digital transmission used extensively in the United States. The DS-1 standard provides a transmission link with a capacity of 1.544 megabits per second (Mbps) over a twisted wire pair. With this capacity, a DS-1 link can handle the equivalent of 24 voice conversations, each digitized at 64 kilobits per second (Kbps). However, with the ever increasing demands that modern technology and the information super highway places upon the communications industry, increasing bandwidth is being demanded. In response to such demand, faster communication links, such as DS-3 transmission links, are being deployed to meet these demands. A conventional DS-3 link provides the equivalent of 28 DS-1 links or a capacity of 44.736 Mbps, which is the equivalent of 672 voice conversations. A DS-3 line typically runs on fiber optic, microwave radio, or coaxial cable lines.
Digital cross-connect systems are often employed in central offices to provide for interconnection between selected communication lines managed by the central office. Such systems typically provide a patching interface that allows the technician to manually change communication line connections through use of patch cords. For certain communication lines, such as high priority lines, it may be imperative that manual access to such lines be restricted at certain times. Moreover, there may be a need or desire to effectively lock out manual access to such communication lines. In the case of high priority lines, and all lines in general, it may be desirable to provide redundant supply power to the line access devices servicing such lines in order to decrease the likelihood that a power related component of the devices will compromise the operation of the line access devices.
There is a need in the industry for an improved cross-connect system and method that provides for controlled patch access to sensitive communications lines. There is a further need for such a system and method that provides for redundant supply power delivery to certain components of the cross-connect system. The present invention fulfills these and other needs.
The present invention is directed to a system and method for providing access to a plurality of communication lines. According to a system embodiment of the present invention, a number of line access devices are provided. Each of the line access devices is coupled to at least one of the communication lines. A patch circuit, associated with each line access device, provides for manually establishing a cross-connection between a first communication line coupled to the respective line access device and a second communication line. A bus couples the first communication line with the patch circuit. A locking circuit is coupled to the bus and the patch circuit. The locking circuit selectively enables and disables patch circuit access to the first communication line in response to a control signal.
The locking circuit preferably employs a make before break contact arrangement for selectively coupling and de-coupling the patch circuit with the first communication line. The locking circuit comprises, or is coupled to, a control device that controls selective enabling and disabling of patch circuit access to the first communication line. The control device is responsive to a control signal received from a local control signal source or a remote control signal source. In one embodiment, the locking circuit is coupled to a user actuatable lock switch. The lock switch, when actuated, generates a control signal that is received by the locking circuit to selectively enable and disable patch circuit access to the first communication line.
In one configuration, the locking circuit is integral with the patch circuit. In another configuration, the locking circuit is located within the communication signal path, but other than in the patch circuit.
The line access devices may each comprise a single line card which incorporates the patch circuit. In this configuration, a primary power supply and a secondary power supply provide redundant supply power to each of the line cards. In another configuration, each of the line access devices comprises a front line card and a rear line card. The front line card incorporates the patch circuit and is coupled to the rear line card via a signal bus. A primary power supply and a secondary power supply provide redundant supply power to at least the front line card of each of the line access devices.
In accordance with another embodiment of the present invention, a method of providing access to a plurality of communication lines involves selecting one of a number of communication lines, and providing patch access for manually establishing a cross-connection between the selected communication line and a second communication line. The method further involves selectively enabling and disabling patch access to the first communication line in response to a control signal. The control signal is received from a local control signal source or from a remote control signal source. Patch access to the first communication line is accomplished on a make before break basis.
Access to the communication lines is provided by a number of line access devices, where each of the line access devices comprises a single line card or a front and rear line card pair. Redundant supply power is provided to the line access devices.
According to a further embodiment of the present invention, a system for providing access to a number of communication lines includes a number of line access devices, with each of the line access devices coupled to at least one of the communication lines. A patch circuit, associated with each line access device, provides for manually establishing a cross-connection between a first communication line coupled to the respective line access device and a second communication line. A signal bus provides for coupling of the first communication line with the patch circuit. A primary power bus provides primary supply power to each of the line access devices. A secondary power bus provides backup supply power to each of the line access devices.
Each of the line access devices, according to one configuration, includes a front line card and a rear line card. The front line card includes a patch circuit and is coupled to the rear line card via the signal bus. The primary power bus provides primary supply power to each of the front line cards and the secondary power bus provides backup supply power to a particular front line card in response to a failure to provide primary supply power to the particular front line card.
According to another configuration, each of the line access devices includes a front line card comprising a DC/DC converter. The primary power bus provides primary supply power to the DC/DC converter of the front line card. A rear line card includes a DC/DC converter, and the secondary power bus provides secondary supply power to the rear line card. The secondary power bus provides backup supply power to the front line card in response to a failure to provide primary supply power to the DC/DC converter of the front line card. The secondary power bus also provides backup supply power to the front line card in response to a failure of the DC/DC converter of the front line card.
Each of the line access devices includes a detector coupled to the primary power bus. The detector detects unintended removal of primary supply power to its respective line access device. The detector couples or otherwise switches backup supply power to its respective line access device in response to detecting removal of primary supply power to its respective line access device.
In one configuration, each of the line access devices includes a front line card comprising a DC/DC converter and a power detector. The primary power bus provides primary supply power to the DC/DC converter of the front line card. A rear line card includes a DC/DC converter. The secondary power bus provides secondary supply power to the rear line card and is coupled to the power detector of the front line card. The power detector couples backup supply power from the secondary power bus to the front line card in response to detecting a failure of the DC/DC converter of the front line card or a failure to provide primary supply power to the DC/DC converter of the front line card.
In yet another configuration, a cross-connect system includes a CPU and a communications card respectively comprising a DC/DC converter. The DC/DC converters of the CPU and communications card provide supply power to the secondary power bus. Each of the line access devices includes a front line card comprising a DC/DC converter. The primary power bus provides primary supply power to the DC/DC converter of the front line card. A rear line card includes a DC/DC converter. The secondary power bus provides supply power to the rear line card, CPU, and communications card. The secondary power bus provides backup supply power to the front line card in response to a failure of the DC/DC converter of the front line card or in response to a failure to provide primary supply power to the DC/DC converter of the front line card.
According a further embodiment of the present invention, a method for providing access to a plurality of communication lines involves providing a number of line access devices. Each of the line access devices is coupled to at least one of the communication lines. Patch access is provided for manually establishing a cross-connection between a first communication line coupled to the respective line access device and a second communication line. Primary supply power is supplied to each of the line access devices. Backup supply power is supplied to each of the line access devices.
Each of the line access devices includes a front line card and a rear line card, with the front line card providing the patch access. Supplying primary supply power involves supplying primary supply power to each of the front line cards. Supplying backup supply power involves supplying backup supply power to a particular front line card in response to a failure to supplying primary supply power to the particular front line card.
In one arrangement, each of the line access devices includes a front line card comprising a DC/DC converter. Supplying primary supply involves supplying primary supply power to the DC/DC converter of the front line card. A rear line card includes a DC/DC converter. Secondary supply power is supplied to the rear line card. Supplying backup supply power involves supplying backup supply power to the front line card in response to a failure to supply primary supply power to the DC/DC converter of the front line card or in response to a failure of the DC/DC converter of the front line card.
According to this arrangement, removal of primary supply power to a particular line access device is detected and backup supply power to the particular line access device is supplied in response to detecting removal of primary supply power to the particular line access device.
In accordance with another arrangement, each of the line access devices includes a front line card comprising a DC/DC converter, and supplying primary supply involves supplying primary supply power to the DC/DC converter of the front line card. A rear line card includes a DC/DC converter, and secondary supply power is supplied to the rear line card. Supplying backup supply power involves supplying secondary supply power as backup supply power to the front line card in response to a failure to supply primary supply power to the DC/DC converter of the front line card or in response to a failure of the DC/DC converter of the front line card.
The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and attainments, together with a more complete understanding of the invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.